Set trigger mechanism



Jan. 29, 1963 M. H. WALKER SET TRIGGER MECHANISM Filed Feb. 3, 1960 INVENTOR.

MER LE H. WALKER 3,975,312 SET TRIGGER MECHANIISM Merie H. Walther, liion, NX., assigner to Remington Arms Company, inc., Bridgeport, Sonn., a corporation of Beiaware Filed Feb. 3, 196e, Ser. No. 6,5@5 6 Ciaims. (Ci. 42-69) This invention relates to fire control means for a firearm and has particular reference to a fire control device of the type generally known as a set trigger.

Set triggers have been known and used for many years, and have as their general objective the provision of fire control means responsive to the slightest pressure and imperceptible movement of the trigger finger of the marksman. With trigger mechanism which can be wished o at the moment when aim is perfect there is a minimum amount of movement `or reflex action which might upset the perfect aim while the bullet is still in the barrel.

At the same time, the highest degree of target accuracy requires a minimum time interval between the conscious decision to fire and the departure of the bullet from the barrel, for during this finite time interval, however short, there is always the possibility of some condition disturbing the perfect aim which should exist when the conscious decision to fire is made.

Obviously, neither of these objectives can be obtained by sacrificing safety and surety of performance. Nithin these limitations the goals of minimum trigger pressure and imperceptible movement have not always been compatible with the goal of minimum lock time. Where the first pair of goals have been attained within the safety limitations, it has often been as a result of the assemblage of such complicated leverage mechanisms that lock time was increased beyond the ability of the marksman to maintain a perfect aim and many of such devices were useful only to the bench rest shooter or other marksman utilizing a comparatively rigid position or support.

The present increased interest in the International Match or Free Riiie type of shooting has focused renewed attention upon fire control devices and other aids to precision shooting adaptable to use in the standing position.

The principal objectives of the present invention are therefore the provision of a safe dependable fire control device which can be set to function with a desired light trigger pull and with imperceptible movement of the trigger. An equally important objective was to achieve the objects mentioned above without involving a sacrifice in lock time.

The exact manner in which these objectives have been accomplished will be pointed out in the following specification, referring to the attached drawing, in which:

FIG. 1 is a side elevational View of the components of my invention.

FiG. 2 is a front elevational view of the same components.

Referring to the drawings by characters of reference, it will be seen that the invention includes two major subassemblies. The first of these sub-assemblies may be identified as the sear assembly 1 which is secured to the receiver of a firearm by two cross-pins Z and 3. The firearm receiver is shown in dotted lines and may be of the type shown in the patent to Walker and Haskell, No. 2,514,981, granted July l1, 1950. The present sear assembly may in fact be substituted bodily for the entire fire control mechanism of that patent.

The second major sub-assembly of my invention may be identified as a set trigger assembly 4 which is adapted to be releasably secured as by the screws 5 and 6 to the floor plate of a firearm stock also shown in dot dash lines.

The sear sub-assembly 1 comprises a sear housing conlz Patented dan. 29,v 1963 sisting of two spaced parallel plates 7 and 8 which receive pins 2 and 3 and support and partially enclose the re mainder of the sub-assembly. Supported on the forward pin 3 is the sear 9 which is formed to dene a striker engaging face 1t?. As in the patent referred to above, the interengaging faces of the sear and the striker l1 are disposed at such an angle that a substantial component of the striker spring force acts at all times to urge the sear t0 swing counter-clockwise about its pivot 3 and against the urging of the sear spring 12 and to thereby remove itself from striker supporting position. This tendency of the sear to disengage itself from the striker is normally resisted by a pivoted sear block 13 which forms a prop under the rear end of the sear. The sear block 13 is mounted on a pivot 14 and provided with a downwardly and forwardly extending arm 15 which upon upward movement causes the sear block to remove support from beneath the rear end of the sear. A sear block spring 16 is provided and tends to rotate the sear block clockwise about its pivot to a position beneath the sear. A cross-pin 17 is provided to serve as a stop, limiting the displacement of the sear block.

Obviously, when the sear block is rotated counterclockwise about its pivot, to remove support from the sear, the sear also will move counter-clockwise about its pivot, and the striker will be released to move forward and override the sear. With the actuating forces removed from the sear block, both springs 12 and 16 act to return the sear and sear block to the striker supporting position which they will assume when the striker is again retracted to cocked position.

The set trigger assembly 4 comprises a generally planar housing 18 which is milled out to leave a recess for the reception of the working components and to define upstanding spacer blocks 19, Ztl and 21. Housing screws 22 are provided, to secure a cover 23 to close the housing. The housing is, as previously noted, secured by screws 5 and 6 in a floor plate secured to a conventional gun stock in a position directly beneath the sear sub-assembly 1.

Fixed pivots and stop pins are either formed integrally from the material of the housing 18 or are secured in bores therein. Although, as has been indicated above, the housing may be formed by machining it out of a solid block, it may also be formed as a lamination of blocks secured to a back plate as by a suitable brazing operation.

The major components mounted in the sub-assembly 4 include a hammer 24 mounted on a pivot 25 and urged to swing upwardly by a spring 26 supported on a pin 27 and reacting against the spacer block 21.

The hammer 24 is held in its lowermost, cocked position by a set sear 28 mounted on a pivot 29 and urged to swing toward the hammer by a spring 3d supported on a pin 31 and reacting against the spacer block 19. The interengaging faces 32 and 53 on the hammer and set sear respectively are so disposed that a component of the hammer spring force is always acting to swing the set sear in a clockwise direction out of holding engagement with the hammer.

A set sear block 34 is mounted on a pivot 35 and provides an abutment 36 which may be placed in opposition to the toe 37 of the set sear to resist the tendency of that member to release the hammer 24. A sear block adju-st ing screw 38 is provided and bears against the spacer 21 to limit the degree of engagement of the abutment 36 with the toe 37. A spring 39 bears against the spacer block 19 with a force which may be regulated by the adjusting screw dit and opposes movement of the set sear block out of engagement with the set sear. A stop screw 41 is provided which comes into engagement with the spacer block 19 when the set sear block is rotated in a clockwise direction to limit actual movement to no more than barely necessary -to release the set sear.

A depending trigger 42 is mounted in the set sear block and may be variably positioned in a fore and aft direction by sliding it along the slot 43 and securing it in a position most convenient to the tirer by the set screw 44. When the ltrigger 42 is pulled to the left the set sear will be released, releasing the hammer 24 which swings upwardly and strikes the sear block arm 15 which in turn releases the sear 9 and the striker 11.

Thehammer 24 may be recocked or the set trigger mechanism set by the operation of the set lever 4S which is, supported on a pivot 46 and has an upwardly extending arm 47 which extends above the hammer and is provided with a crosspin 48 and bushing 49 rotatable thereon and overlying the hammer. A set lever spring 50 is provided, to no-rmally return the set lever tothe position shown in the drawing, where a stop 51 places a limit upon its movement.. ,Y

When the set lever is manually rotated in a counterclockwise direction about the pivot 46, the bushing 49 is-brought into engagement with the top of the hammer 24 to cockthe same against the forcey of the spring 30 and return it to the control of the set sear.

The set trigger unit is made removable, so that one set trigger may be used interchangeably on several ries of different caliber, to permit easy maintenance and adjustment, and to permit replacement by a more conventional trigger unit Yacting directlyv on the arm` 15 for use in those matches where set triggers are not permissible.

The effectiveness of this mechanism in reducing lock time of set trigger mechanisms may be seen'V from the fact that with this mechanism the lock time of a double set trigger mechanism has been reduced to nearly that of the direct acting mechanism of the Walker et al. patent referred to above and yet we are safely able to reduce the trigger pull to very low values. Lock time as Vhere referred4 to means thetime interval between the application of pressure to the trigger and the engagement of thefiiriug pin with the primer.

disengagng movement of said set sear, a trigger mounted on and extending directly from said pivoted set sear block for manual direct actuation of said set sear block, said set sear and said set sear block being the only members disposed between said hammer and said trigger, and a setting lever engageable with the hammer to recock same after release.

2. A set trigger mechanism as dened'in claim 1, said Set sear block being provided with adjustable members limiting the amount of engagement of the set sear block with the set sear and limiting the amount of travel of the set sear block in the direction of releasing'the set sear.

3. A set Vtrigger mechanism as defined in claim 2, said set sear block being provided with spring means opposing movement of said set sear block in a direction to release said set sear, and adjustable means regulating the force of said spring means.

4. A set trigger mechanism as defined in claim 3, said hammer, set sear, set sear block, trigger and setting lever, being mounted in a unitary sub-assembly which is removable from the rifle as an integral unit, for adjustment or maintenance;

5. A set trigger mechanism for controlling the release of a rearm striker, comprising a swingably mounted sear which is: urged by a component of the forcesV acting on the firearm striker to swing tota position disengaged from the striker, a pivotally mounted sear block having a free end engaged beneath the sear to' oppose swinging move- For example, the conventional Model 1903 Springfield Y rifle has a lock time of about 8` milliseconds, while the direct acting re control mechanism which is'thefsubject of the Walker etl al. patent, No. 2,514,981, has a lock time of about 2.5 milliseconds. Conventional double set trigger mechanisms have lock times onV the order of ll to 12V milliseconds. The Canjar single set trigger, which is the fastest of the available commercial units, has, when applied to the trigger of the Walker et al; patent mechanism, a lock time of about`5.5 milliseconds.

In contrast, the double set trigger of this invention permitsflock Vtime of 4.5 milliseconds or less -to be achieved withsafe and dependable performance.

Although the specification and drawing have been coniined to the illustration of a single embodiment, it will be obvious that'equivalent arrangements are possible and will be resorted toy as the art develops'. Accordingly, reference should be made to the claims for a definition of the scope of the invention.

I claim: Y

l. A settrigger mechanism for controlling the release of a firearm striker, comprising a swingably mounted sear Y which is urged by a component of the forces acting yon the firearm striker to swing to a positiondisengaged from the striker, a pivotally mounted sear block having a free end engaged beneath the sear to oppose swinging movement thereof, an arm extending from said sear block, a pivotally mounted spring-urged hammer positioned to swing into operative engagement With said arm todisengage-said sear block from beneath the sear, a set sear comprising a single swingably mounted holding member directly inv holding engagement with said hammer and urged by a component of the spring forcesV acting thereon to swing said set sear out of holding engagement with said hammer, a pivoted set sear block comprising a single swingably mounted blocking member directly opposed to said set sear and engaged therewith to prevent hammer ment thereof, an arm extending from said sear block, a pivotally mounted spring-urged hammer positioned to swingV into operative engagement with said arm to disengage said sear block from beneath the sear, a set sear com-A pris-ing a single swingably mounted holding member directly in holding engagement with said hammer and urged by a component of the spring forces acting thereon to swing said set sear out of holding engagement with said hammer, a; pivoted sear block comprising a single swingably mounted blocking'member directly opposed to said set sear and engaged therewith to prevent hammer disengaging movement of said set sear, a trigger mounted on and extending directly from said pivoted set sear block for manual direct actuation of said set sear block, saidv set sear and said set sear block being the only members disposed between said hammer and said trigger, and a setting lever engageable with the hammer to recock same after release, said set sear block being provided with means to accept and releasably retain said set trigger in selected positions permitting selection of the most convenient position for the firers operating finger', said means -to accept Vthe trigger comprising a longtiudinally slotted portion of said set sear block to receive said trigger, said trigger being positionable in said slot at any selected position between the extremes thereof, and said means to releasably retain said trigger comprising'locking means to secure said ltrigger in any selected positionV in said sear block.

6. A set trigger mechanism for controlling the release ofa spring-urged striker mounted in a firearm receiver which is in turn supported in a firearm stock, said set trigger mechanism comprising a sear engageable withv the striker to hold same in a cocked position, and a sear controlling member, both mounted on said receiver, and a set ltrigger sub-assembly removably mounted in said firearm stock for actuating said sear controlling member,V

said sub-assembly comprising a hammer spring-urged to movev in a direction to operatively engage the sear con-V 5 6 extending directly from said set sear block for manual di- References Cited in the file of this Pelt rect actuation of said `set sear block, said set sear and said UNHED STATES PATENTS set Sear block being the only members disposed between 2 M9 232 mnh uly 1 5 1941 said hammer and said trigger, and a setting lever engagea- 295808 QV d -"t" Ma im 1960 ble with the hammer to recock same after release by said 5 Oo mug e a y set seaL 554,287 Germany July 7, 1932 

1. A SET TRIGGER MECHANISM FOR CONTROLLING THE RELEASE OF A FIREARM STRIKER, COMPRISING A SWINGABLY MOUNTED SEAR WHICH IS URGED BY A COMPONENT OF THE FORCES ACTING ON THE FIREARM STRIKER TO SWING TO A POSITION DISENGAGED FROM THE STRIKER, A PIVOTALLY MOUNTED SEAR BLOCK HAVING A FREE END ENGAGED BENEATH THE SEAR TO OPPOSE SWINGING MOVEMENT THEREOF, AN ARM EXTENDING FROM SAID SEAR BLOCK, A PIVOTALLY MOUNTED SPRING-URGED HAMMER POSITIONED TO SWING INTO OPERATIVE ENGAGEMENT WITH SAID ARM TO DISENGAGE SAID SEAR BLOCK FROM BENEATH THE SEAR, A SET SEAR COMPRISING A SINGLE SWINGABLY MOUNTED HOLDING MEMBER DIRECTLY IN HOLDING ENGAGEMENT WITH SAID HAMMER AND URGED BY A COMPONENT OF THE SPRING FORCES ACTING THEREON TO SWING SAID SET SEAR OUT OF HOLDING ENGAGEMENT WITH SAID HAMMER, A PIVOTED SET SEAR BLOCK COMPRISING A SINGLE SWINGABLY MOUNTED BLOCKING MEMBER DIRECTLY OPPOSED TO SAID SET SEAR AND ENGAGED THEREWITH TO PREVENT HAMMER DISENGAGING MOVEMENT OF SAID SET SEAR, A TRIGGER MOUNTED ON AND EXTENDING DIRECTLY FROM SAID PIVOTED SET SEAR BLOCK FOR MANUAL DIRECT ACTUATION OF SAID SET SEAR BLOCK, SAID SET SEAR AND SAID SET SEAR BLOCK BEING THE ONLY MEMBERS DISPOSED BETWEEN SAID HAMMER AND SAID TRIGGER, AND A SETTING LEVER ENGAGEABLE WITH THE HAMMER TO RECOCK SAME AFTER RELEASE. 